Dry farming may therefore be to playing a role in an agroecological transition in the region, buoying small-scale, thought-intensive management styles with access to a steady income source and consumer base. However, with recent droughts and water shortages in California, dry farming has recently begun to take a more prominent role in social and policy visions for the future of the state’s agricultural system. From the Sustainable Groundwater Management Act to emergency orders in drought years, farmers, researchers, policymakers, and the general public have become acutely aware of California’s currently unsustainable agricultural water use and the economic ramifications of water shortages . As an option that holds promise for maintaining farmer livelihoods while dramatically cutting water use, journalists and policy groups have touted dry farming as an important system to target for significant expansion . Farmers have been considering how to use dry farming to adapt to drier futures for decades, lighting the way for researchers and policymakers’ more recent interest. However, up to this point, farmers’ thoughts and knowledge about dry farming have not been clearly elicited or formally incorporated into conversations about the future of the practice. Grounding conversations about future expansion of the practice in the knowledge of those who are most intimately familiar with its implementation is essential. At this moment of enthusiasm for dry farming, rolling benches we look to practitioners to better understand the current state of dry farming on the Central Coast and its potential for expansion across California, along with the benefits and harms that expansion may carry.

We interviewed ten dry farmers, representing over half of the commercial dry farm tomato operations on the Central Coast, in order to collaboratively answer two central research questions. First, what business and land stewardship practices characterize successful tomato dry farming on California’s Central Coast? And second, what is the potential for dry farming to expand beyond its current adoption while maintaining its identity as a diversified practice that benefits small-scale operations? The majority of these farmers were part of an ongoing participatory research project in which field data were collected to better understand soil fungal communities and nutrient management in dry farm systems . These interviews were extensions of conversations and relationships fostered with farmers throughout the research process. We synthesized farmer insights into nine key themes that broadly describe how dry farming is currently practiced on the Central Coast, its potential to expand in scope , and the opportunities that farmers see as particularly provident for the practice. At this juncture of a high-functioning, low-water management system and urgent political interest in decreasing agricultural water use–in California and across the globe–we conclude by asking how dry farming can be a model for developing systems that decrease water use, and also how dry farming itself may be scaled out to other small-scale, thought-intensive operations without jeopardizing these same farms’ ability to continue profitably growing dry farm produce.Interviews were done with farmers who have commercial operations in California’s northern Central Coast region , as well as one farm with operations in Marin and Sonoma counties. Ranges of coastal mountains govern both climate and land use, trapping cool, moist air, and concentrating farming operations in valleys with fertile, alluvial soils.

The Central Coast is known for its agricultural production–particularly berries, lettuce, and artichokes–that thrive in its fertile soils and mild climates that allow for year-round cultivation. Agricultural revenue in the region totals over $8 billion annually , making it a larger agricultural producer than most countries. This intensive production has led to both high land values and environmental degradation–largely in the form of water contamination–that shape both farmer decision-making and policy interventions . Within this landscape, farms often operate at industrial scales, though many small farms persist. Though cropland is consolidated into fewer, large operations , many smaller farms have found niches selling to local markets.After building relationships over the course of a year-long participatory field research process with eight tomato dry farmers , we conducted semistructured interviews with all farmers involved in that study. We interviewed two additional dry farmers who were not involved in the field project–one whose farm is in Sonoma County , and one whose farm could not participate in the field study due to extensive fire damage–for a total of ten farmers representing eight operations. Interviews were done in person , over the phone , and on Zoom in winter and fall 2022. Because there is no official record of tomato dry farmers in the Central Coast region, we used a snowball approach to identify farms that might be candidates for inclusion, asking each interviewee what other dry farm operations they knew of in the area. We can identify two dry farm tomato growers in the region who were not interviewed in this study, and we estimate that our interview subjects represented 50-75% of commercial dry farm tomato operations on California’s Central Coast. Interviews lasted 1-2 hours and focused on dry farm management practices, environmental constraints, support, water/land access, and economics . Interviews were recorded and transcribed, then analyzed through an interactive process of open, axial, and selective coding .

Data were grouped into three overarching categories , with key themes in each category. Each theme was mentioned in at least half of the interviews.In order to identify areas that might be suitable for future tomato dry farm management, we used farmer-described constraints to make a suitability map using publicly available datasets. We first compiled the environmental constraints on tomato dry farming described in each interview , which fell into three main categories: precipitation, temperature, and soil texture. We limited our analysis to California as the region these farmers are most familiar with to avoid extrapolating constraints beyond the context in which they were given. We used PRISM 30-year climate normals to characterize California’s temperature and precipitation . We used the average constraint named by the farmers; however, because these normals are a 30 year average and will stray significantly from these averages in individual years, particularly in the case of precipitation, we expect that we overestimate the extent of suitable areas. As California’s temperatures get hotter and precipitation becomes increasingly variable with climate change , we expect a further systematic overestimation of suitable areas identified based on the past 30 years of weather data. For the suitability analysis we assigned temperature and soil texture to three categories that were each associated with a score: good , tolerable , and intolerable , while precipitation was divided into ranges that were suitable with no additional irrigation, suitable with additional irrigation, and unsuitable.For temperature, we considered the average maximum temperature in the three hottest months of the growing season , categorizing them separately with the scores described above . We then multiplied these three categorized scores together and took the cube root to get temperature suitability scores for the state, also excluding any areas whose monthly 30-year minimum temperature was above 59o F. We followed a similar procedure for soil texture, using SSURGO estimates of clay content averaged across soil horizons at a 90m resolution . Because farmers did not give numeric estimates of how much clay was needed in dry farm soils, we made sure our defined ‘tolerable’ range encompassed the full range of clay content observed in participating farms’ soils . To define the ‘good’ range , we excluded the farm with the lowest clay content, which was also the only farm where farmers stated that they could not grow tomatoes of a high enough quality to consistently market them as “dry farm.” We multiplied temperature and soil scores to make a preliminary suitability map. This multiplication reflects the interaction between temperature and soil texture, rolling grow table in which good texture can compensate for higher temperatures by increasing soil water holding capacity, and lower temperatures can lessen the evapotranspirative demand that would be particularly problematic for plants growing in sandier soils with a lower soil water holding capacity. We then separated the dataset into three areas based off of farmers’ understandings of where tomato dry farming could occur with no added irrigation and where it could occur with supplemental irrigation , and excluding areas that would not get enough winter rain to grow a suitable winter cover crop . The final map shows suitability scores in all areas that are categorized a ‘cropland’ in the 2019 National Land Cover Database . These areas are superimposed onto groundwater basins categorized as high priority in California’s Sustainable Groundwater Management Act . Crop totals on land that was deemed suitable for tomato dry farm management in these areas were calculated using the 2021 Cropland Data Layer .By focusing on the characteristics that limited water can give a tomato, these farmers highlight a recurring theme in understanding the functional definition of dry farming tomatoes. As the Central Coast faces increasingly limited water availability, the idea of dry farming has gained traction among policymakers purely by virtue of offering a means to continue farming while maintaining a restricted water budget.

However, these farmers are quick to recognize that dry farming is only a management style that they can afford to choose for their operations insofar as it can excite customers and return a reasonable profit. In this way, the product that dry farming creates, which is valuable enough to consumers that they are willing to pay a significant premium for it, is the outcome that defines the management approaches farmers can use. Farmers know that they could alter the schedule for the minimal irrigation they do put on their dry farm tomatoes to increase yields . However, while defining the practice by some maximum threshold of water application, and then choosing to allocate irrigation water to maximize yields, may be appealing from a water savings perspective, farmers recognize that they must define the practice in terms of outcomes and not inputs. Farmers must produce what consumers have come to expect from a dry farm tomato if they are going to make dry farming an economically viable choice for their operation.To better understand where tomatoes might conceivably be farmed in California given the environmental constraints identified above, we modeled dry farm suitability on California cropland as a function of precipitation, temperature, and percent clay in soil. The resulting map shows what lands could potentially support a dry farm crop, with and without supplemental irrigation, using constraints that are relaxed to encompass the least restrictive farmer-elicited constraints . The map therefore errs on the side of including land that is not an ideal candidate for dry farming, rather than leaving off land that may potentially be a good fit. With rising temperatures and less reliable rainfall, this map, which is based off of 30-year normals, likely also systematically overestimates what areas might fall into these thresholds when projecting into future climatic conditions. All areas in blue indicate land that meets a threshold where dry farming could be considered in a non-drought year without adding any irrigation. Areas in orange indicate that, while there is likely enough rain to sustain a winter cover crop, some amount of irrigation would often be needed to grow a successful dry farm crop. Areas in darker colors connote land that falls in conditions that are closer to ideal, whereas lighter colors indicate that more conditions are tolerable, rather than ideal, for dry farming. It is crucial to note that areas that show up as “suitable” on the map–including the most ideal locations–will likely require years of diversified management for soils to build the water holding capacity and fertility that allow for peak dry farm performance. These areas should therefore be considered candidates for long-term dry farm management, rather than ready-to-go dry farm fields. Because the constraints used to build the model were elicited specifically with regard to tomatoes, this of course is not a comprehensive map of everywhere that might be considered for dry farming non-tomato crops. Particularly when it comes to grains and perennials , the range of possible locations is likely much broader. In the case of grains, winter varietals can be planted that take advantage of rain in winter months, while tree crops have far more extensive root systems that can reach water well beyond that which might be available to a tomato, in both cases relaxing the temperature and precipitation constraints that tomatoes need to survive without irrigation.